His relationship with the villains could also change. Without One for All, he might not be as much of a target initially. But as he grows in other ways, he could become a different kind of threat to the villains, one that they didn't expect. Maybe he'd be seen as a symbol of the quirkless rising up, which could both inspire and enrage the villains.
His relationship with All Might would be very different. Instead of being a successor, he might become more of a protege in a general sense. All Might could still mentor him, but their bond wouldn't be centered around One for All.
With his classmates, Izuku would no longer be the one with the special power passed down from a great hero. He might be more of an underdog, and some classmates could either look down on him or be more protective of him. For example, Bakugo might not see him as a rival in the same way.
With the teachers, they would have to treat Izuku differently. They might give him more individual attention and training. For example, Aizawa could be more hands - on in helping Izuku control his quirk better. As for villains, they might see Izuku as an easier target at first, but then realize he's a force to be reckoned with on his own.
If Naruto doesn't become Hokage, his relationship with Sasuke might be less strained. Since there's no need to compete for the top position in the village, they could focus more on their friendship. They might go on missions together more often just for the sake of adventure and to protect each other.
His relationship with Midoriya would become more complex. Since Midoriya originally had One for All, there could be some tension as Shoto now has the power. But they could also bond over sharing this special ability, training together to figure out new ways to use it.
One possible storyline could be that Izuku discovers a different quirk within himself. Maybe a latent quirk that was overshadowed by his admiration for All Might and One for All. For example, he could have a quirk related to intelligence amplification, which would make him a brilliant strategist in hero battles.
With Sakura, she might initially be disappointed as she always saw Naruto as a strong ninja. However, she could also come to support him if she realizes that he is following his heart. And for his other friends like Shikamaru and Kiba, they might be more accepting. Shikamaru might even admire Naruto for having the courage to break away from the expected path.
With his classmates, some might be scared of Izuku. They've known him as a kind - hearted person, but the All for One quirk has such a dark reputation. However, some like Ochaco might try to understand him better and support him through his journey with this new quirk. His relationship with the teachers would also be under scrutiny. They would need to ensure that Izuku doesn't use the quirk for evil purposes, which could lead to a lot of extra monitoring and a sense of unease in their interactions.
His relationship with All Might would become extremely complicated. All Might, who passed on One For All, would be shocked and perhaps a bit disappointed that Izuku now has the All For One quirk. He might question his decision to choose Izuku as his successor. With Bakugo, their rivalry could take a different turn. Bakugo might be both envious and afraid of Izuku's new power, leading to more intense confrontations. And with his friends like Iida and Ochaco, they might be initially hesitant around Izuku, not knowing if he can still be trusted with such a villainous - associated quirk.
His relationship with All Might would also be affected. All Might might be more cautious about Izuku's quirk as it's very powerful and could potentially disrupt the fabric of time. Izuku, on the other hand, could use his quirk to go back and learn more about All Might's past, which could strengthen their bond as he gains a deeper understanding of his mentor. However, it could also create a rift if Izuku discovers something in the past that he doesn't like about All Might's actions.
Regarding his friends like Shikamaru and Kiba, Naruto would be more accessible. As Hokage, he would be very busy, but without that role, he could spend more time with them. They could all go on more missions together as a team, strengthening their friendships in a different way than if Naruto was in a position of leadership.
His relationships with his friends would likely become more complex. If he starts using his time quirk to change things, his friends might not remember the original timeline, but Izuku would. This could create a sense of isolation for him as he holds memories that no one else does.